Wireless devices and related wireless communication techniques and protocols have become ubiquitous in modern society. Indeed, the prior art is replete with wireless devices such as cellular telephones, mobile computers, personal digital assistants, digital media players, portable video game devices, and the like. Moreover, portable medical devices having wireless data communication capabilities are becoming increasingly popular, especially for patients that have conditions that must be monitored on a continuous or frequent basis. For example, diabetics are usually required to modify and monitor their daily lifestyle to keep their body in balance, in particular, their blood glucose (“BG”) levels. Individuals with Type 1 diabetes and some individuals with Type 2 diabetes use insulin to control their BG levels. To do so, diabetics routinely keep strict schedules, including ingesting timely nutritious meals, partaking in exercise, monitoring BG levels daily, and adjusting and administering insulin dosages accordingly. Diabetics may utilize wireless medical devices that are deployed in a network environment in a manner that facilitates data communication between two or more separate devices.
The prior art includes a number of insulin pump systems that are designed to deliver accurate and measured doses of insulin via infusion sets (an infusion set delivers the insulin through a small diameter tube that terminates at a cannula inserted under the patient's skin). In lieu of a syringe, the patient can simply activate the insulin pump to administer an insulin bolus as needed, for example, in response to the patient's current BG level. A patient can measure his BG level using a BG measurement device, such as a test strip meter, a continuous glucose measurement system, or the like. BG measurement devices use various methods to measure the BG level of a patient, such as a sample of the patient's blood, a sensor in contact with a bodily fluid, an optical sensor, an enzymatic sensor, or a fluorescent sensor. When the BG measurement device has generated a BG measurement, the measurement is displayed on the BG measurement device. A continuous glucose monitoring system can monitor the patient's BG level in real time.
Insulin pumps and continuous glucose monitoring devices may also be configured to communicate with remote control devices, monitoring or display devices, BG meters, and other devices associated with such an infusion system. For example, a continuous glucose monitoring sensor may include a wireless radio frequency (“RF”) transmitter that communicates with a BG monitor device within the infusion system. As another example, the infusion system may include a handheld remote control that communicates with the infusion pump device using wireless techniques.
Conventional wireless systems, including many wireless medical device systems, rely on synchronized beacons, which are utilized to manage wireless communication between wireless network devices. Beacons are usually transmitted at predetermined and fixed intervals, and the beacon interval is known by the transmitting and receiving devices. Knowledge of the beacon interval allows the receiving device to “wake up” from its power saving mode at the appropriate time to receive the beacons according to the designated interval schedule. In many systems, such as a conventional wireless medical device system, the beacon interval is a fixed interval that is based upon the fastest response time needed by a device within the system. Unfortunately, this type of configuration results in excessive power consumption because the beacon transmitting devices must support the fixed beacon interval even during periods when no data needs to be communicated. In turn, excessive power consumption leads to reduced battery life and/or more frequent battery recharging cycles, or requires increasing the size of the battery (and, therefore, the device itself) to accommodate beacon transmissions.